A NUMERICAL AND EXPERIMENTAL STUDY OF THE ROTOR INLET FLOW FIELDS OF RADIAL TURBINES USING VANED AND VANELESS STATORS

摘要

This paper describes experimental and numerical investigations of the flow fields delivered to the inlet of a radial turbine rotor by vaned and vaneless stators, and to what extent they influence the stage performance. The work focussed on the flow fields delivered to the inlet of an 86mm turbine by 3 pairs of vaned and vaneless housings, each pair having matching flow capacities. Static pressure measurements at rotor inlet were acquired, and from these the circumferential flow distributions at rotor inlet were directly compared. The experimental results were used to validate numerical models to study the rotor inlet flow fields in greater detail. Both numerical and experimental results highlighted the vaneless stators to deliver a higher level of uniformity at rotor inlet. The comparatively higher levels of non-uniformity in the vaned stator builds can be primarily attributed to jet and wake effects, as these were found not to have mixed out significantly at the rotor inlet and contributed both to the overall levels of pressure loss and higher variations of rotor inlet incidence. Comparisons have been made to previously reported turbine performance data, and the influence of the rotor inlet flow field on stage running performance has been discussed.